Participation of the host protein(s) in the morphogenesis of bacteriophage P22

Summary Spontaneous mutants of S. typhimurium resistant to thiolutin are conditionally non-permissive for phage P22 development (Joshi and Chakravorty 1979). At 40° C non-infective phage particles are produced. Phage development in two nonpermissive hosts (18/MC4 and 153/MC4) has been studied in detail. The steps at which the phage morphogenesis is interfered with differ in the two mutants. The electron micrograph of the particles produced in the mutant 18/MC4 reveals the presence of normal-looking particles; these particles contain phage DNA, adsorb to the permissive host but fail to inject their DNA. The particles produced in the mutant 153/MC4 which fail to adsorb to the host are found to be tail fibre-less. These observations indicate the involvement of host protein(s) in phage P22 morphogenesis.     

Determination of ochratoxin A in liquorice products using HPLC-based analytical methods. Part II: harmonised method and method validation study

On the basis of the outcome of an European proficiency test series conducted on behalf of the CAOBISCO (Association of the Chocolate, Biscuit and Confectionery Industries of the EU) expert group on ochratoxin A, a new harmonised method was developed for the analysis of ochratoxin A in liquorice extracts. This method works without the use of halogenated solvents because, as the proficiency test showed, an aqueous extraction solution can be used instead of, for example, chloroform, whose use is restricted in the EU. The main objective of this method validation study was to check the performance of this harmonised method. To carry out the method validation study, a set of three different test samples (one liquorice powder and two liquorice pastes) and a liquorice powder sample with an indicated range of ochratoxin A (a so-called sunshine sample) was distributed to 21 laboratories in ten countries throughout Europe and to one laboratory in the USA. The study was evaluated according to internationally recognised guidelines. In terms of its repeatability and reproducibility for determining ochratoxin A in liquorice extracts with a relative standard deviation for repeatability (RSD_r) of between 6.68 and 19.95 and a relative standard deviation for reproducibility (RSD_R) of between 17.39 and 29.08 the performance of the harmonised method was found to be in the accepted range of the EU directive for the analysis of mycotoxins in several foodstuffs.     

Superinfection exclusion and changes in cellular transport processes in phage infected Salmonella typhimurium.

Summary The changes induced by bacteriophage P22 in the cellular transport process(es) of the host Salmonella typhimurium (Taneja et al., 1975; Khandekar et al., 1975; Bandyopadhyay and Chakravorty, 1976) involve interactions between the superinfection exclusion system of the resident prophage and the C immunity region of the superinfecting phage. The sieA gene of the prophage interferes with the changes in the cellular transport process induced by the superinfecting phage. However, if the superinfecting phage carries active C ₁ and C ₂ genes of the superinfecting phage seem to be expressed in the sie A⁺ lysogen.     

β-Resorcylic Acid Derivatives,with Their Phytotoxic Activities,from the Endophytic Fungus Lasiodiplodia theobromae in the Mangrove Plant Xylocarpus granatum

Nine new β-resorcylic acid derivatives, (15S)-de-O-methyllasiodiplodin ( 1 ), (13S,15S)-13-hydroxy-de-O-methyllasiodiplodin ( 2 ), (14S,15S)-14-hydroxy-de-O-methyllasiodiplodin ( 3 ), (13R,14S,15S)-13,14-dihydroxy-de-O-methyllasiodiplodin ( 4 ), ethyl (S)-2,4-dihydroxy-6-(8-hydroxynonyl)benzoate ( 5 ), ethyl 2,4-dihydroxy-6-(8-hydroxyheptyl)benzoate ( 6 ), ethyl 2,4-dihydroxy-6-(4-methoxycarbonylbutyl)benzoate ( 7 ), 3-(2-ethoxycarbonyl-3,5-dihydroxyphenyl)propionic acid ( 8 ), and isobutyl (S)-2,4-dihydroxy-6-(8-hydroxynonyl)benzoate ( 9 ), together with a known ethyl 2,4-dihydroxy-6-(8-oxononyl)benzoate ( 10 ) were obtained from Lasiodiplodia theobromae GC-22. The structures of these compounds were elucidated by extensive spectroscopic analyses. Compounds 1 , 3 , and 6 showed growth inhibitory effects against Digitaria ciliaris. Conversely, treatment with compounds 5 , 6 , 7 , 9 , and 10 stimulated elongation activity toward the root of Lactuca sativa. These data expand the repertoire of new β-resorcylic acid derivatives that may function as lead compounds in the synthesis of new agrochemical agents.     

Response of rhizobacterial communities in watermelon to infection with cucumber green mottle mosaic virus as revealed by cultivation-dependent RISA

We investigated the rhizobacterial densities and community structure in watermelon rhizosphere under the infection of cucumber green mottle mosaic virus (CGMMV) by artificial inoculation. Rhizobacterial densities and communities were analysed from healthy and infected plants under aerobic and anaerobic culture techniques. The highest total number of aerobic rhizobacteria was counted to be 2.7 × 10⁸ colony forming units per gram (CFU · g^?1) and anaerobic rhizobacteria was to be 3.2 × 10⁶ CFU · g^?1, in healthy and infected plants, respectively. Cultivation-dependent ribosomal intergenic spacer analysis (RISA) was employed for further analysis on the rhizobacterial community structure. By incorporating the relative abundance of amplicons, the per cent similarity was determined by the similarity coefficients based only upon the absence or presence of DNA bands. The cluster analysis of RISA showed that the community structure of aerobic rhizobacteria exhibited 60% similarity between healthy and infected plant. The highest community structure similarity (50% similarity) of anaerobic rhizobacteria occurred between before planting and infected plant.     

Association of five candidate genes with fatty acid composition in Korean cattle

Fatty acid composition of meat is becoming more important due to consumer demand for high quality and healthy foods. The present study evaluated the associations of five candidate genes (FABP4, FASN, NR1H3, GH and SCD) with fatty acid composition in Korean cattle (Hanwoo). The g.3691G > A single nucleotide polymorphism (SNP) in the FABP4 gene had significant effects on high myristic acid (C14:0; P < 0.01) and palmitic (C16:0; P < 0.05) in animals having the GG genotype, and high arachidonic acid (C20:4; P < 0.05) in the AA genotype of Hanwoo. The FASN SNP at position g.17924G > A was also significantly associated with myristic acid (P < 0.01). In case of the SCD gene, a significant effect was only observed in myristoleic acid (C14:1; P < 0.01). However, SNPs in GH and NR1H3 genes showed no effects on fatty acid composition. The results indicate that SNPs in three candidate genes, FABP4, FASN and SCD, may be influential in breeding design for fatty acid composition in Hanwoo.     

Physical mapping and characterization of bacteriophage 9NA genome

The DNA of bacteriophage 9NA, a virulent phage ofSalmonella typhimurium, is linear, double stranded, circularly permuted and is approximately 56 kilobase pairs long. The 9NA genome is partially methylated. A physical map of the DNA has been constructed using the restriction endonucleasesBamHI,BglII,SmaI andPvuII. The putative packaging end (‘pac’ end) and the direction of packaging of the concatemeric DNA has been postulated.     

Gene m3 mediated efflux of intracellular leucine from bacteriophage P22 infected Salmonella typhimurium

Infection of $\text{Salmonella}\text{typhimurium}$ with the $\text{m}{}_3$ mutant of bacteriophage P22 leads to a rapid and severe efflux of intracellular leucine. The superinfection exclusion ($\text{sie}$) genes of P22 interfere with the function of $\text{m}{}_3$ gene, the product(s) of which is speculated to be an internal protein of phage P22.